Meet the world's 24 superbillionaires

In 1987, Forbes published its first billionaires list, featuring 140 individuals whose combined wealth totaled $295 billion. At the time, the richest person in the world was Japan's Yoshiaki Tsutsumi, a real estate tycoon worth $20 billion.

- Katherine Clarke

Today, the world's richest person, Elon Musk, is worth $419.4 billion, roughly 21 times as much as Tsutsumi at his peak and more than two million times as much as the median net worth of an American household, according to exclusive data from global wealth intelligence firm Altrata.

As the ranks of global billionaires have swelled dramatically in recent years, a new category of ultrarich has emerged-the superbillionaire. Musk is one of just 24 people worldwide who qualify for that distinction, which is defined as individuals worth $50 billion or more.

As of early February, those superbillionaires' fortunes accounted for more than 16% of all billionaire wealth, a dramatic increase from 4% in 2014, according to Altrata. Their combined net worth totaled $3.3 trillion, equivalent to the nominal GDP of France. Of those 24 people, 16 qualified as centi-billionaires, meaning they have a net worth of at least $100 billion.

The rise of the superbillionaire has coincided with a significant leap in luxury markets across the world, including real estate, as these individuals cobble together massive portfolios of luxury homes around the globe.

Experts say the data shows how the ranks of the ultrarich have begun to pull away from the merely wealthy, and how a subset has been propelled to new heights.

"Billionaires have always obviously controlled significant amounts of wealth, but now you're talking about differences in the billionaire population themselves," said Maya Imberg, head of thought leadership and analytics at Altrata, who has been researching the superbillionaire set. "It's quite staggering just how much the net worths of some of these people have grown."

In major luxury real-estate markets like New York, Miami, Palm Beach, Los Angeles and Aspen, new supertall towers and spec mansions have popped up geared specifically to the billionaire set and there has been an explosion of nine-figure home sales across the country.